The invention relates to a cleaning machine with means for blasting the goods to be cleaned by means of liquid containing granules, comprising a treatment chamber for receiving the goods, a liquid container, pump means the suction side of which is connected to the liquid container for sucking-in liquid, nozzle means connected to the pressure side of the pump means for ejecting liquid towards the goods in the treatment chamber, and means for supplying granules to liquid supplied to the nozzle means, and for separating granules from liquid ejected from the nozzle means.
Cleaning machines in which blasting of the goods to be cleaned is applied are used for instance for washing heavily soiled goods with adhering food residues which are difficult to resolve and remove only by spraying liquid containing conventional dishwashing detergents. In a prior art embodiment (DAS No. 1.148,360) of a dishwashing machine of this type, commonly called heavy-duty dishwashing machine, the granules are located on a grid in the treatment chamber below the goods to be washed, and by forcing liquid from below through the grid said granules are thrown towards the goods together with the liquid. The arrangement is not satisfactory because the liquid containing granules cannot without difficulty be directed towards the goods to be washed in such a manner that an optimally effective cleaning of the goods is achieved. In another embodiment (U.S. Pat. No. 1,761,492) granules formed as balls are introduced by means of an injector into the liquid when it is ejected towards the goods to be washed, and are then separated from the liquid again by means of a grid when the liquid leaves the goods, to be forwarded to the injector by means of separate conveyor means in order to be introduced into the liquid again. Such an arrangement is effective per se, but the conveyor means provides a complication because it fails easily during operation of the machine and can hardly operate with relatively small granules.
The invention aims at providing a cleaning machine of the type initially referred to in which the granules are supplied and separated by means of a constructively simple arrangement in a reliable manner also as far as small granules are concerned, and which at the same time provides the possibility to direct the liquid containing granules by means of the nozzle means in the most suitable angle of incidence towards the goods in order to obtain an optimally effective cleaning of the goods.
In order to achieve this the cleaning machine according to the invention is characterized in that the last-mentioned means comprises a liquid-permeable compartment which is located inside the liquid container with a bottom outlet in the treatment chamber connecting to the liquid container via the liquid-permeable compartment, and in that this compartment is connected through a valve-controlled opening to the suction side of the pump means for supplying the granules to the liquid through this opening such that liquid containing the granules is sucked-up and circulated by the pump means, or alternatively retaining the granules in the liquid-permeable compartment such that liquid only is sucked-up and circulated by the pump means.
In an introductory part of a cleaning cycle during the so-called prerinsing it may be desired to wash off and collect material adhering relatively loosely to the goods before the washing proper is started by blasting the goods by means of the liquid containing granules, because such blasting will not be particularly efficient as far as thick and relatively soft layers of contaminants are concerned, e.g. such food residues on the goods to be washed, which have not got dried or have burnt to such goods. Also detergents are not particularly efficient when acting upon such soft and sometimes perhaps rather thick layers of contaminants.
In order to spray the goods to be cleaned, with liquid only while detached contaminants are being separated from the liquid there is arranged in the bottom outlet, according to a further development of the invention, an adjustable member coordinated with the valve control for passing liquid from the treatment chamber directly to the liquid-permeable compartment and, alternatively, through a strainer in the bottom outlet.